A method of manufacturing a solid-rolled railway wheels
(57) Abstract:The invention relates to metallurgy, in particular to the technology of solid-rolled railway wheels. The technical result of the invention is the provision of properties in the disk and the wheel rim when surfacing with the rolling heat at the level corresponding to the heat with separate heating. The technical result is achieved due to optimization of the end temperature of deformation and temperature quenching of the wheel, namely the temperature of the end of the plastic deformation of the support in the interval 960-880°C, and the temperature of the wheel before hardening in the interval 940-780°C, and the duration poslerevolutsionnoi pause before hardening is not more than 150 C. for 1 h.p. f-crystals, 2 tab. The invention relates to metallurgy, in particular, to a technology of solid-rolled railway wheels.A known method of manufacture of railway wheels, comprising heating the billet to a temperature of 1270oC, continuous deformation by the press wheel and the mill with the end of the deformation at a temperature of 1050 - 1100oC, isothermal aging at a temperature of 650oC, heat treatment with the STV wheels however, is long-lasting and energy-intensive.Closest to the present invention is a method of manufacture of railway wheels, comprising heating the workpiece under deformation to a temperature of 1270oC, the deformation of the presses and the mill with the end of the deformation at a temperature of 1050 - 1100oC, the hardening of the wheel rim after deformation and his leave.The disadvantage of this method is low plastic characteristics of the metal rim and unstable impact strength of the wheel due to the poor structure formed at high temperature end of deformation (the size of the actual grain is 2-4 points).The objective of the invention is to develop a method of manufacture of railway wheels, providing properties in the disk and the wheel rim when surfacing with the rolling heat at the level corresponding to the heat with separate heating.The technical result in achieving the properties of the metal of the rim and disk-level heat with separate heating is achieved by optimizing end temperature deformation and temperature quenching of the wheel, namely the temperature akonaditray 940 - 780oC, and the duration poslerevolutsionnoi pause before hardening is not more than 150 C.The invention consists in the following.In the temperature range of end deformation 960 - 880oC and subsequent hardening rolling heating 940 - 780oC structure is formed in the disk and the wheel rim, providing a level properties of these elements in accordance with the requirements of GOST 10791. The size of the actual grain in the disk and the rim in the proposed temperature range the end of the deformation and before hardening, respectively and 4-6 6-8 points.Different grain size in the disk and the wheel rim due, in particular, endured varying degrees of deformation and conditions poslerevolyutsionnogo cooling of these elements of the wheel. So, in the rim and the wheel disc maximum altitude deformation, respectively 60 and 90%, and the speed poslerevolyutsionnogo cooling wheel disc greatly exceeds the rate of cooling of the massive rim that defines the different velocity recrystallization in these elements of the wheel.The proposed temperature range the end of the deformation depending on the content of coal is round the end of the deformation at specified intervals and depending on the carbon content averaged structure and mechanical properties of the metal disk and the rim. Thus, the higher temperature end of the deformation for the bottoms with low carbon content (0,53 - 0,57%) can reduce the number of structurally free ferrite and the distance between pearlite colonies in the perlite, which improves tensile strength of the metal at high resource ductility and toughness provide low carbon content. At high carbon content (0,63 - 0,67%) lowering the temperature of the end of the deformation increases resource of plasticity and toughness, which is achieved by increasing the number of structurally free ferrite and of distance between pearlite colonies in perlite, and additional grind the actual grain.The cumulative impact of these structural factors allows to obtain the mechanical properties of the rim and disc in accordance with the requirements of GOST 10791.The temperature range of the wheel before hardening rolling heating is 940 - 780oC and depending on the carbon content and is within:
C, % -oC
0,53 - 0,57 - 940 - 840
0,58 - 0,62 - 910 - 810
0,63 - 0,67 - 880 - 780
Temperature limits before hardening in each of the 3 groups on the carbon content aboslutely according to the proposed method is not more than 150 C.So, after transportation of the wheel to tempering machine maximum temperature before hardening for each of the 3 groups on carbon, respectively 940, 910 880oC. the Maximum temperature before hardening of the wheel in accordance with the maximum duration poslerevolutsionnoi pause 150, according to the proposed method, for each of the 3 groups on carbon, respectively 840, 810, 780oC.Limit the duration poslerevolutsionnoi pause equal to 150 s, attributable to the following: with increasing duration poslerevolutsionnoi pause over 150 with reduced values of the plastic characteristics of the wheel rim, which is associated with the processes of recrystallization and growth of austenite grains and as a consequence increase the size of the pearlite colonies.An example implementation of the method.For industrial sampling method were selected three groups of blanks with carbon content, respectively, or 0.57, 0.62 to 0.67%. Manganese concentration was almost the same and amounted to 0.75 of 0.77%. After heating to a temperature of 1240oC blanks were predeterminately on units forging-rolling line, including the following technologically advanced, and the temperature value of the end of the deformation and temperature before hardening of the wheel, and also the vacation mode in accordance with the proposed method and technology of the prototype are shown in table 1.The test results of the wheels, made by the proposed method and in accordance with the prototype are shown in table 2.As shown, the regulation of the temperature of the end of the deformation and the temperature of the wheel before hardening allow us to greatly increase the level values of the plastic characteristics and toughness. 1. A method of manufacturing a solid-rolled railway wheels, comprising heating the workpiece to 1200 - 1240oWith the strain containing the precipitate, forming, rolling and vyybkw wheel, intermittent quenching and tempering, characterized in that the temperature of the end deformation of the support in the range of 960 - 880oTo carry out Polideportivo a pause with a duration of no more than 150 to the temperature of the wheel before quenching in the range 940 - 780oC.2. The method according to p. 1, characterized in that the intermittent quenching is carried out at a vertical location of the wheel.
FIELD: heat treatment of parts made in form of bodies of revolution from metal materials; cooling of monoblock wheels, tires, wheel discs and similar discs and rings such as railway wheels and tram wheels, gear wheels and sprockets.
SUBSTANCE: first, scale is removed from one and the same device by one and the same method to improve its mechanical properties and then mechanical properties are determined and reproduced through complex cooling performed in functional zone; cooling processes are different for different sections; parts are cooled at control or adjustment in "on-line" mode due to spraying or blowing-off by one cooling medium.
EFFECT: enhanced efficiency.
27 cl, 2 dwg
SUBSTANCE: invention relates to thermal treatment field. For providing of solidity not less than 300 HB on depth not less than 50 mm from surface of volution wheel tread, exclusions during the process of cooling of formation of hardening structures and providing of maximal drop of residual voltage, solid-rolled wheels made of steel with carbon content no less than 0.60 wt % is heated till the austenitising temperature and intensively cooled, at that during the cooling process from the moment of the beginning for 50-100 seconds it is implemented increasing of cooling intensity of comb roll surface and side surfaces of crown by all height from 0 till value 2-3 W/(cm2·s), then it is cooled during 40-300 sec with constant refrigeration rate of specified wheel face equal to value 2-3 W/(cm2·s) for providing of strengthening in all crown volume.
EFFECT: providing of material strengthening.
2 dwg, 3 tbl
SUBSTANCE: wheel pair is installed and fixed in rotating facility. Matte coating eliminating reflection of laser beam is applied on surface subject to treatment with CO2-laser. Focusing system is adjusted so, that diametre of laser radiation spot corresponds to a chosen mode. Required rates of wheel pair rotation and laser beam transfer are set by means of program controlled device. Compressed air blows off a flare of products of combustion into exhaust ventilation; laser treatment is carried out under a chosen mode to obtaining geometry of paths of laser strengthening eliminating melting zones of thermal effect and mutual overlapping of laser strengthening paths.
EFFECT: increased wear resistance of roll surface and crest of wheel pair due to increased hardness and due to obtaining high dispersed structure of strengthened zone.
SUBSTANCE: plasma surface hardening is performed by plasma generator with work gas flow converter that has slit-like outlet. Flow converter face surface is made to fit processed part shape. In processing, slit-like outlet is located at α=30-60° to generatrix of converter face surface. Processing is performed with overlap of processing strip, overlap length making l≥h·-tgα, where h is the processing strip width.
EFFECT: notably reduced extension strain, higher efficiency of surface hardening.
2 cl, 2 dwg
FIELD: machine building.
SUBSTANCE: metal surface strengthening is carried out by means of low temperature plasma arc of direct action. As plasma generating gas there is used argon, mixture of argon with helium, and mixture of argon with carbon containing gases. Also, heating is performed with magnetic oscillation of arc with triangle shape of voltage pulse, scanning amplitude 20-45 mm and distance of treatment 10-30 mm. A strengthened surface layer consists of several sub-layers: at depth of 0.2-0.8 mm - structure of martensite with inclusions of upper bainite, - from 0.8 to 1.8 mm - trosto-martensite structure, - from 1.8 to 2.5 mm - sorbitic-martensite structure, - from 2.5 to 3 mm - sorbite, - over 3 mm - ferrite-pearlite structure of basic metal.
EFFECT: raised efficiency of strengthening process, 3 times increased wear resistance of strengthened working zone of wheel, 3 times reduced probability of development of hydrogen metal brittleness and tendency to brittle fracture.
2 cl, 1 tbl
SUBSTANCE: cooling of working layer of rim during the first 180 sec is performed at discrete increase in flow rate of cooler of 0.0005 to 0.02 l/(cm2/s) by 0.0001 l(cm2/s) every 15-30 sec and the next 120 sec at constant flow rate of cooler to 0.5 l/(cm2/s), and cooling of end surface of rim on the ridge side is performed with air with flow rate of 0.5 m3/(cm2/s); then, wheel is cooled in the air and tempering is performed.
EFFECT: high application properties of railroad wheels owing to improving wear resistance of working layer of wheel rim and mechanical properties of wheel disc; heating to austenisation temperature and differentiated cooling of working layer of rim and its face on the ridge side is performed during 300 s.
1 ex, 2 tbl
SUBSTANCE: hardening is performed at 810-850°C. Tempering is performed at 450-500°C. Then, plasma treatment with plasmotron with energy density of 106-108 W·m-2 is performed. Nitrogen is used as plasma-forming gas. Plasma treatment of tread contact surface and wheel flange surface is performed. Transformer of working flow of plasma-forming gas, which is profiled as to shape of treated surface, is used. Wheel is rotated during treatment about its axis at certain speed. Wheel rotation speed is determined as per ratio n=K·(1/Dw), where n - speed of wheel rotation about its axis, rpm; K - empirical coefficient equal to 20-2000 revolutions·mm/min; Dw - diameter of treated wheel, mm.
EFFECT: increasing strength and thickness of reinforced layer; improving quality and efficiency of plasma strengthening process; simplifying the process diagram of strengthening plasma treatment.
2 dwg, 1 ex
SUBSTANCE: first, wheel is heated for formation of austenite in all sections of a rim and a disk. Then, wheel is cooled for formation of bainite/martensite microstructure in the disk section. Wheel is cooled for formation of bainite/martensite microstructure in the rim inner section. Wheel is cooled for formation of bainite/martensite microstructure in the rim outer section.
EFFECT: providing required mechanical properties of steel and increasing wheel service life.
10 cl, 7 dwg, 1 tbl
FIELD: process engineering.
SUBSTANCE: invention relates to thermomechanical processing of parts and can be used for surface hardening of friction working surfaces of rails and rolling stock wheels. Particularly, it relates to surface hardening of wearing surfaces of parts, primarily, rolling surfaces and railway mounted axle flanges. Strips with modified structure are produced that feature mechanical properties other than those of mother metal. Note here that said strips vary in width and depth over the wheel flange circle.
EFFECT: higher wear resistance, longer wheel life.
1 tbl, 7 dwg, 1 ex
FIELD: process engineering.
SUBSTANCE: invention relates to metallurgy, particularly, to heat treatment of binding bands. Railway bands made of steel containing the components that follow are subjected to heat treatment: C 0.65-0.75 wt %, Mn 0.6-0.9 wt %, Si 0.22-0.45 wt %, Cr 0.2-0.6 wt % and V 0.01-0.03 wt %. Band is heated to austenising temperature and subjected to controlled cooling nu liquid coolant or air-water mix, surface cooling being performed by water with controlled flow rate: 0.00035 l/(cm2·s) for up to 120 s, 0.00075 l/(cm2·s) for 121-150 s, 0.00115 l/(cm2·s) for 151-180 s, 0.00155 l/(cm2·s) for 181-210 s, 0.002 l/(cm2·s) for 211-300 s. Note here that side surface in the band inner diameter is air cooled with flow rate of 0.0003 m3/(cm2·s) with subsequent holding in air and tempering.
EFFECT: higher wear resistance of working play, contraction strains in working ply to 50-60 mm depth from rolling surface.
5 tbl, 1 ex